In self-propelled forage harvesters, the chopper drum, due to its rather large moment of inertia, has a relatively long run-down time after the drive has been turned off. In case an operator should rely on the chopper drum being stopped and open the protection arrangement of the chopper drum shortly after the drive is turned off in order to remove a crop jam or in order to clean the machine, the operator is thereby exposed to a high potential danger. It has been proposed that an alarm signal be given when the chopper drum is rotating in order to call the operator's attention to the fact that the chopper drum is still rotating. However, such alarm signals are given when the operator does not intend to obtain any access to the chopper drum, and therefore are sometimes regarded as disturbing. Furthermore, they do not remove the danger emanating from the chopper drum.
DD 219 651 A proposes a drive for chopper arrangements that includes a brake for the supply arrangement and the drive of the front attachment, which also acts upon the chopper arrangement. The brake is automatically actuated by a foreign object signaling arrangement. Hence, it is used only to protect the chopper drum against foreign object intrusion. It cannot counteract the danger originating from the chopper arrangement, when the operator turns off the drive, since then the chopper arrangement continues to rotate without any braking.
U.S. Pat. No. 4,974,711 A describes the control of the brake and the clutch of a lawn mower. In view of the considerably smaller moment of inertia of the knives of the lawn mower, anyone skilled in the art cannot see a reason for the use of this control for an agricultural harvesting machine of type described initially from this publication.
The problem underlying the invention is seen in the need to define a solution that makes possible an access without any danger to the operator after turning off the drive of a crop processing arrangement of a harvesting machine.